The development of asymmetry for oscillatory flow within a tube containing sharp edge periodic baffles

Zheng, Mingzhi and Li, Jie and Mackley, M. R. and Tao, Jianjun (2007) The development of asymmetry for oscillatory flow within a tube containing sharp edge periodic baffles. Physics of Fluids, 19 (11). pp. 114101-15. DOI 10.1063/1.2799553

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Abstract

This paper investigates the evolution of asymmetric patterns for oscillatory flow in a baffled tube. A numerical simulation for three-dimensional flows in an axisymmetric geometry was developed and compared with experimental results obtained using particle image velocimetry (PIV). Sharp edged baffles were used for both numerical simulations and experiments. From the numerical simulation, a stability map of the flow symmetry was obtained as a function of Reynold-Strouhal numbers. The simulations show that for all Strouhal numbers, the flow was axisymmetric at Reynolds numbers less than 100 and asymmetric at Reynolds numbers larger than 225. The flow was less stable to asymmetric disturbances at small or large Strouhal numbers when compared to St = 1.0. In particular, the flow in the region St<0.5 and Re>100 was asymmetric. Two mechanisms for vortex instability transition into three dimensions has been identified. At small Strouhal numbers, the primary mechanism is a shear (Kelvin-Helmholtz) instability. At larger Strouhal numbers, the axisymmetry of the flow is broken because of the collision of travelling eddies that have been shed from opposite baffles. The numerical results are in general in agreement quantitatively with the experimental observations and both experiment and simulation assist in understanding the development of unsteadiness in periodic reversing flows.

Item Type: Article
Uncontrolled Keywords: 2007 AREP BPI 2007 P IA55
Subjects: 99 - Other
03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
Journal or Publication Title: Physics of Fluids
Volume: 19
Page Range: pp. 114101-15
Identification Number: 10.1063/1.2799553
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:04
Last Modified: 23 Jul 2013 09:54
URI: http://eprints.esc.cam.ac.uk/id/eprint/841

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